Filter unit events to their units, rework energytick, drop macrotweak

Eight commits off classicapi_next.

ClassicAPI's RegisterUnitEvent registers for an event but only delivers it
when arg1 is one of the given units, so a handler for one unit stops waking
for every other one in the world. The 26 registrations whose unit set is
fixed at registration time now name it. The rule throughout is register the
superset and keep the handler's own check -- the filter narrows what arrives,
it does not decide what to act on. Guards that look unreachable stay put: the
filter applies only when arg1 is a string, so an event that fires with a
number or no argument is delivered as if plainly registered.

Frames whose unit changes at runtime own their subscriptions instead of
sorting events out per event. unitframes points them at the unitstr
UpdateVisibility already computes -- replacing a string concat, and on a miss
a second concat plus a UnitGUID call, for every frame on every unit event in
the world -- and a frame that is not in use drops its unit events entirely.
nameplates registers per plate against the plate's own token, which is also
the only workable shape: slots have no cap, so any nameplate1..N list would
have been a guess that fails in exactly the crowded scenes where plates
matter. marktracking names mark1 through mark8. A registration keeps its
kind, so none of these can be plain-registered first.

Both teardown paths PLAYER_LOGOUT guards -- the crash 132 -- now cover the
per-frame subscriptions: plates tear down rather than dispatching through
logout, and a unit frame takes itself off the visibility scan so it cannot
re-register what it just dropped.

marktracking also drops its once-a-second full rebuild, which ran for the
whole session whether or not a marker existed anywhere. The ticker is created
and cancelled with group membership. It is deliberately not keyed on a mark
being visible -- a marker on an out-of-range unit shows no row, and that is
the case the poll exists to catch.

nameplates gates the per-plate update against the floor across all four
throttle categories before classifying it, instead of running a GetAlpha, a
castbar IsShown, a cast lookup and up to two libthrottle:Get resolutions on
plates throttled to 10fps that were going to return anyway. Nothing that
would have updated can be turned away by a floor. The four throttles resolve
in CacheConfig, where config changes already land.

energytick sweeps the clock the server actually runs. There is one regen
timer for every power, re-armed every 2s by Player::RegenerateAll and never
touched by casting; the five-second rule changes what a tick pays, not when
it lands. The sweep is a free-running phase lock on that clock, so
Illumination refunds, potions and a Mana Spring totem on its own phase no
longer snap the spark mid-cycle, and an 80ms band keeps a correct tick from
hitching it at the wrap. The FSR window shades rather than predicting a share
of spirit the client cannot compute -- the Casting Regen item ladder is equip
auras absent from the buff list. The energy period is summed from
SPELL_AURA_MOD_ENERGY_REGEN_TIME across the spellbook and buffs, so Blade
Rush is found without GetTalentInfo(2, 16), an ordinal that does not fail
when the tree changes but reads another talent's rank.

macrotweak is gone -- ClassicAPI 1.15 covers it -- with its config entry, its
GUI block, its translations in all eight locales, and actionbar's
ButtonMacroScan, the #showtooltip scanner that fed it.

api/unitframes.lua

@@ -314,7 +314,8 @@ function pfUI.uf:UpdateVisibility()
   end
 
   local unitstr = ("%s%s"):format(self.label or "", self.id or "")
-  self:SetAttribute("unit", unitstr ~= "" and unitstr or nil)
+  self.unitstr = unitstr ~= "" and unitstr or nil
+  self:SetAttribute("unit", self.unitstr)
   local visibility = ("[target=%s,exists] show; hide"):format(unitstr)
 
   -- Group frames are redundant when the group is already shown as a raid grid:
@@ -344,6 +345,15 @@ function pfUI.uf:UpdateVisibility()
      self.visible = nil
   end
 
+  -- This is the single place a frame's unit is ever assigned, so it is also the
+  -- place its subscriptions follow it to: the engine then delivers only this
+  -- unit's events, and OnEvent compares against the cached string instead of
+  -- rebuilding label..id -- and calling UnitGUID -- for every unit event fired
+  -- by anything, anywhere. A frame that is not in use drops them entirely; the
+  -- roster events that would bring it back are registered plainly, and
+  -- visibilityscan re-runs this every 0.2s regardless, so it recovers on its own.
+  self:RegisterUnitEvents(visibility ~= "hide" and self.unitstr or nil)
+
   -- vanilla visibility
   if self.unitname then
     self:Show()
@@ -624,11 +634,14 @@ function pfUI.uf:UpdateConfig()
       f.feedbackText:ClearAllPoints()
       f.feedbackText:SetPoint("CENTER", f.portrait, "CENTER")
     end
-    f:RegisterEvent("UNIT_COMBAT")
+    f.combatfeedback = true
   else
     f.feedbackText:Hide()
-    f:UnregisterEvent("UNIT_COMBAT")
+    f.combatfeedback = nil
   end
+  -- RegisterUnitEvents owns UNIT_COMBAT; clearing the cached unit makes the
+  -- next UpdateVisibility re-run it against the new combatfeedback state.
+  f.eventunit = nil
 
   f.hpLeftText:SetFontObject(GameFontWhite)
   f.hpLeftText:SetFont(fontname, fontsize, fontstyle)
@@ -918,6 +931,9 @@ function pfUI.uf:UpdateConfig()
     f:UpdateFrameSize()
   else
     f:UnregisterAllEvents()
+    -- that dropped the unit filters along with the registrations, so the cache
+    -- has to go too or the next UpdateVisibility believes they are still set
+    f.eventunit = nil
     f:Hide()
   end
 end
@@ -959,6 +975,10 @@ function pfUI.uf.OnEvent()
     this:UnregisterAllEvents()
     this:SetScript("OnEvent", nil)
     this:SetScript("OnUpdate", nil)
+    -- visibilityscan is a separate frame and keeps ticking, so leaving this one
+    -- on its list would have UpdateVisibility re-register the unit events we
+    -- just dropped -- straight back into the crash 132 this branch prevents
+    visibilityscan.frames[this] = nil
     return
   end
   
@@ -1025,8 +1045,12 @@ function pfUI.uf.OnEvent()
     this.update_aura = true
   elseif this.label == "pet" and event == "UNIT_HAPPINESS" then
     this.update_full = true
-  -- UNIT_XXX Events
-  elseif arg1 and (arg1 == this.label .. this.id or (UnitGUID and arg1 == UnitGUID(this.label .. this.id))) then
+  -- UNIT_XXX Events. RegisterUnitEvents means arg1 can only be this frame's own
+  -- unit; the compare is kept for the case the filter sits out, which is when
+  -- arg1 is not a string. The old GUID alternative is gone: these events fire
+  -- once per token that resolves to the unit AND once with the raw GUID, so the
+  -- token form always arrives and the GUID form was only ever a duplicate wake.
+  elseif arg1 and arg1 == this.unitstr then
     if event == "UNIT_PORTRAIT_UPDATE" or event == "UNIT_MODEL_CHANGED" then
       this.update_portrait = true
     elseif event == "UNIT_AURA" then
@@ -1251,25 +1275,56 @@ function pfUI.uf.OnUpdate()
   end
 end
 
+-- The unit events whose arg1 is the frame's OWN unit -- everything the OnEvent
+-- routes through its "UNIT_XXX Events" branch. These are not registered here:
+-- UpdateVisibility owns them, because it owns the frame's unit (below).
+--
+-- UNIT_PET and UNIT_HAPPINESS are deliberately absent. Their branches key on
+-- the frame's label, and UNIT_PET's arg1 is the pet's OWNER ("player" for a
+-- "pet" frame), so filtering them by the frame's own unit would drop them.
+local UNIT_EVENTS = {
+  "UNIT_DISPLAYPOWER",
+  "UNIT_HEALTH", "UNIT_MAXHEALTH",
+  "UNIT_MANA", "UNIT_MAXMANA",
+  "UNIT_RAGE", "UNIT_MAXRAGE",
+  "UNIT_ENERGY", "UNIT_MAXENERGY",
+  "UNIT_FOCUS",
+  "UNIT_PORTRAIT_UPDATE", "UNIT_MODEL_CHANGED",
+  "UNIT_FACTION",
+  "UNIT_AURA", -- frame=buff, frame=debuff
+}
+
+-- Point this frame's unit-event subscriptions at `unitstr`, or drop them when
+-- the frame has no unit. Cheap to call repeatedly: it no-ops unless the unit
+-- actually changed, which matters because visibilityscan runs UpdateVisibility
+-- for every frame five times a second.
+function pfUI.uf:RegisterUnitEvents(unitstr)
+  if self.eventunit == unitstr then return end
+  self.eventunit = unitstr
+
+  for i = 1, table.getn(UNIT_EVENTS) do
+    if unitstr then
+      self:RegisterUnitEvent(UNIT_EVENTS[i], unitstr)
+    else
+      self:UnregisterEvent(UNIT_EVENTS[i])
+    end
+  end
+
+  -- UNIT_COMBAT rides along only while the frame draws combat feedback text.
+  -- UpdateConfig clears eventunit when it toggles that, so the next
+  -- UpdateVisibility re-runs this.
+  if unitstr and self.combatfeedback then
+    self:RegisterUnitEvent("UNIT_COMBAT", unitstr)
+  else
+    self:UnregisterEvent("UNIT_COMBAT")
+  end
+end
+
 function pfUI.uf:EnableEvents()
   local f = self
 
   f:RegisterEvent("PLAYER_ENTERING_WORLD")
   f:RegisterEvent("PLAYER_LOGOUT")
-  f:RegisterEvent("UNIT_DISPLAYPOWER")
-  f:RegisterEvent("UNIT_HEALTH")
-  f:RegisterEvent("UNIT_MAXHEALTH")
-  f:RegisterEvent("UNIT_MANA")
-  f:RegisterEvent("UNIT_MAXMANA")
-  f:RegisterEvent("UNIT_RAGE")
-  f:RegisterEvent("UNIT_MAXRAGE")
-  f:RegisterEvent("UNIT_ENERGY")
-  f:RegisterEvent("UNIT_MAXENERGY")
-  f:RegisterEvent("UNIT_FOCUS")
-  f:RegisterEvent("UNIT_PORTRAIT_UPDATE")
-  f:RegisterEvent("UNIT_MODEL_CHANGED")
-  f:RegisterEvent("UNIT_FACTION")
-  f:RegisterEvent("UNIT_AURA") -- frame=buff, frame=debuff
   f:RegisterEvent("PLAYER_AURAS_CHANGED") -- label=player && frame=buff
   f:RegisterEvent("PLAYER_EQUIPMENT_CHANGED") -- label=player && frame=buff (ClassicAPI: weapon-enchant buffs)
   f:RegisterEvent("PARTY_MEMBERS_CHANGED") -- label=party, frame=leaderIcon
@@ -1387,6 +1442,7 @@ function pfUI.uf:CreateUnitFrame(unit, id, config, tick)
   f.UpdateConfig     = pfUI.uf.UpdateConfig
   f.EnableScripts    = pfUI.uf.EnableScripts
   f.EnableEvents     = pfUI.uf.EnableEvents
+  f.RegisterUnitEvents = pfUI.uf.RegisterUnitEvents
   f.EnableClickCast  = pfUI.uf.EnableClickCast
   f.GetColor         = pfUI.uf.GetColor
 
@@ -1503,6 +1559,9 @@ function pfUI.uf:CreateUnitFrame(unit, id, config, tick)
     f:UpdateFrameSize()
   else
     f:UnregisterAllEvents()
+    -- that dropped the unit filters along with the registrations, so the cache
+    -- has to go too or the next UpdateVisibility believes they are still set
+    f.eventunit = nil
     f:Hide()
   end