fix(deps): update gastown patch and pin beads to Go 1.24 compatible version

- Update gastown-fix-agent-bead-address-title.patch line numbers (326→315)
  for current upstream gastown source
- Remove obsolete gastown patches (rig-prefix, copydir-symlinks) that are
  now handled upstream
- Pin beads to 55e733c (v0.47.2) which uses Go 1.24.0 - newer versions
  require Go 1.25.6 which isn't in nixpkgs-unstable yet
- Remove beads-search-query-optimization.patch as it targets newer code

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

flake.lock

@@ -8,15 +8,16 @@
         ]
       },
       "locked": {
-        "lastModified": 1769405733,
-        "narHash": "sha256-WpROnW0dRi5ub0SlpKrMBs3pYlSBY4xw22hnTNvBMgI=",
+        "lastModified": 1768533782,
+        "narHash": "sha256-+5wZHjGfe2bf+FUDc99avz+ASc8Qx34QVkd85s0VU/U=",
         "owner": "steveyegge",
         "repo": "beads",
-        "rev": "6e82d1e2eea121ce5dc0964d554879f8b0c08563",
+        "rev": "55e733cf624a94c63257a657970f1fc9a287883d",
         "type": "github"
       },
       "original": {
         "owner": "steveyegge",
+        "ref": "55e733c",
         "repo": "beads",
         "type": "github"
       }
@@ -81,11 +82,11 @@
     "gastown": {
       "flake": false,
       "locked": {
-        "lastModified": 1769538736,
-        "narHash": "sha256-A33gyS/ERUCFcaFG9PJdIHfIOafguqkRe+DuIZteH5s=",
+        "lastModified": 1770098007,
+        "narHash": "sha256-CFlN57BXlR5FobTChdE2GgdIGx4xJcFFCk1E5Q98cSQ=",
         "owner": "steveyegge",
         "repo": "gastown",
-        "rev": "177094a2335786d1d450fd9e14b935877291c004",
+        "rev": "13461161063bf7b2365fe5fd4df88e32c3ba2a28",
         "type": "github"
       },
       "original": {