feat: comprehensive enhancement — cache optimization, session mind, orchestrator, multi-credential, codebase indexer

Core Features:
- Session Mind with persistent memory across sessions
- Orchestrator + Worker subagent architecture
- Multi-credential OAuth with auto-refresh
- Codebase indexer and watcher connectors
- Footer status bar with live metrics

Cache & Prompt Optimizations:
- Move mindContext/failureContext to stable system prefix (BP1 cached)
- Large tool result cache_control breakpoints (>7000 chars)
- Deterministic message wrapping (PR anomalyco#21535)
- Tool evidence digest through compaction (PR anomalyco#21492)
- O(1) queue dequeue + single-flight summary (PR anomalyco#21507)
- Levenshtein O(min(N,M)) space optimization (PR anomalyco#21500)
- Three-phase image auto-compression (PR anomalyco#21371)
- ContextUsage and NewSession tools (PR anomalyco#21399)
- E2E cache integration tests with real Anthropic OAuth

Session snapshot resets prevent memory leaks on session delete.

Author: fairyhunter13

.claudeignore

@@ -0,0 +1,39 @@
+# Prevent Claude Code from reading large generated/binary files
+# Each file read costs tokens — exclude irrelevant content
+
+# Build artifacts
+dist/
+ts-dist/
+.turbo/
+.sst/
+
+# Dependencies
+node_modules/
+vendor/ai/node_modules/
+vendor/opentui/zig-out/
+
+# Lock files (large, low signal)
+bun.lock
+
+# Generated snapshots
+packages/opencode/src/provider/models-snapshot.ts
+
+# Binary/compiled
+*.wasm
+*.o
+*.so
+*.dylib
+
+# Test fixtures and scripts (not needed for reasoning about code)
+packages/opencode/test/automation/
+packages/opencode/test/token-compare/
+packages/opencode/test/e2e/*.sh
+
+# Vendored CLAUDE.md (not our project instructions)
+vendor/ai/CLAUDE.md
+vendor/opentui/CLAUDE.md
+
+# IDE/editor
+.idea/
+.vscode/
+.codex/