fix(topdata): let pinned TLK ids evict stale state owners (#48)

## Problem

The custom palette taxonomy (#46) pins display strings to fixed TLK ids in `tlk/custom.tlk.yml`, and `registerInlineAtID` demanded each pinned id be free. But `.tlk_state.json` is **gitignored and per-machine** — each dev grows their own copy, and before #46 every ref got its id dynamically (first-come-first-served).

On any machine whose state predates #46, a ref could have already parked on a now-pinned id. That fails the build:

```
topdata validation failed with 1 error(s): error: native topdata buildability check failed:
TLK id 2689 is already reserved by "feat:yuanti/alternate_form.feat"
```

It only passes on machines whose state was regenerated after #46 (pinned window already clean). The `allocateID` reserved-skip that #46 added protects a *fresh* build, but does nothing about a *stale cache*.

## Fix

Make the pin authoritative over the per-machine cache. A stale cached owner sitting on a pinned id is evicted and reallocated a fresh id when next made active; only two pins fighting over the same id in `custom.tlk.yml` is now an error. This self-heals on the next build — no manual `.tlk_state.json` deletion needed.

Caveat: the evicted ref's strref shifts on affected machines. That's unavoidable (something must move off the pinned id), and dynamic strrefs were never stable across machines anyway.

## Tests

Added `TestBuildStandaloneTLKPinEvictsStaleStateOwner` (seeds a pre-#46 state with a feat parked on the pinned id, asserts the build succeeds, the pin owns it, and the feat is reallocated). Full `internal/topdata` suite + `go vet` pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)Reviewed-on: #48
Reviewed-by: xtul <mpiasecki720@protonmail.com>
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>

internal/topdata/topdata_test.go

@@ -2449,6 +2449,55 @@ strings:
 	}
 }
 
+func TestBuildStandaloneTLKPinEvictsStaleStateOwner(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data", "feat"))
+	mkdirAll(t, filepath.Join(root, "topdata", "tlk"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "feat", "base.json"), `{
+	  "output": "feat.2da",
+	  "columns": ["LABEL", "FEAT", "DESCRIPTION"],
+	  "rows": [{
+	    "id": 0,
+	    "key": "feat:test",
+	    "LABEL": "TEST_LABEL",
+	    "FEAT": {"tlk": {"key": "feat:test.name", "text": "Test Feat"}},
+	    "DESCRIPTION": "****"
+	  }]
+	}`+"\n")
+	writeFile(t, filepath.Join(root, "topdata", "tlk", "custom.tlk.yml"), `schema: sow-topdata/tlk/v1
+base_strref: 16777216
+strings:
+  - key: sow.module.name
+    text: Shadows Over Westgate
+    id: 50
+`)
+	// Simulate a per-machine state that predates the pinned taxonomy: the feat
+	// ref dynamically grabbed id 50 on an older build, exactly where the pin
+	// now lives. The build must self-heal instead of failing.
+	writeFile(t, filepath.Join(root, "topdata", tlkStateFile),
+		`{"version":1,"language":"en","entries":{"feat:test.name":{"id":50}}}`+"\n")
+
+	if _, err := BuildNative(testProject(root), nil); err != nil {
+		t.Fatalf("BuildNative failed on stale pin collision: %v", err)
+	}
+
+	stateRaw, err := os.ReadFile(filepath.Join(root, "topdata", tlkStateFile))
+	if err != nil {
+		t.Fatalf("read tlk state: %v", err)
+	}
+	var state tlkStateDocument
+	if err := json.Unmarshal(stateRaw, &state); err != nil {
+		t.Fatalf("parse tlk state: %v", err)
+	}
+	if state.Entries["sow.module.name"].ID != 50 {
+		t.Fatalf("pin must own id 50, got %#v", state.Entries["sow.module.name"])
+	}
+	if got := state.Entries["feat:test.name"].ID; got == 50 {
+		t.Fatalf("stale feat ref should have been reallocated off id 50, got %d", got)
+	}
+}
+
 func TestBuildPreservesTLKStateAcrossTextChanges(t *testing.T) {
 	root := testProjectRoot(t)
 	mkdirAll(t, filepath.Join(root, "topdata", "data", "skills"))