feat(targets): add multi-target CLI adapter system (Droid support)

Implement target adapter pattern enabling CCS CLI to support multiple backend targets
(Claude, Droid) via pluggable adapters. Core additions:

- TargetAdapter interface for pluggable target implementations
- ClaudeAdapter and DroidAdapter concrete implementations
- Target registry (singleton Map-based storage)
- Target resolver with precedence: --target flag > per-profile config > busybox detection
- Droid config manager with atomic writes and file locking to ~/.factory/settings.json
- Droid binary detector to validate runtime environment
- Adapter dispatch integrated into ccs.ts main execution flow
- ccsd busybox alias for seamless Droid invocation
- --target flag documentation in help
- Session tracking enriched with target metadata
- Dashboard target badge for visual identification

Testing:
- 43 unit tests covering resolver, registry, config manager, and adapters
- Full coverage of target detection logic and edge cases

Documentation:
- Refactored system-architecture.md into modular docs/system-architecture/ subdirectory
- Updated code-standards.md with target adapter guidelines
- Updated codebase-summary.md with architecture overview
- Updated maintainability baseline (33.8% → 35.2%)

This establishes extensible foundation for multi-target support without breaking
existing Claude workflows. Droid adapter is production-ready but defaults to Claude
for backward compatibility.

bun.lock

@@ -21,6 +21,7 @@
         "listr2": "^3.14.0",
         "open": "^8.4.2",
         "ora": "^5.4.1",
+        "proper-lockfile": "^4.1.2",
         "ws": "^8.16.0",
       },
       "devDependencies": {
@@ -40,6 +41,7 @@
         "@types/express-session": "^1.18.2",
         "@types/js-yaml": "^4.0.9",
         "@types/node": "^20.19.25",
+        "@types/proper-lockfile": "^4.1.4",
         "@types/ws": "^8.5.10",
         "@typescript-eslint/eslint-plugin": "^8.48.0",
         "@typescript-eslint/parser": "^8.48.0",
@@ -397,10 +399,14 @@
 
     "@types/normalize-package-data": ["@types/normalize-package-data@2.4.4", "", {}, "sha512-37i+OaWTh9qeK4LSHPsyRC7NahnGotNuZvjLSgcPzblpHB3rrCJxAOgI5gCdKm7coonsaX1Of0ILiTcnZjbfxA=="],
 
+    "@types/proper-lockfile": ["@types/proper-lockfile@4.1.4", "", { "dependencies": { "@types/retry": "*" } }, "sha512-uo2ABllncSqg9F1D4nugVl9v93RmjxF6LJzQLMLDdPaXCUIDPeOJ21Gbqi43xNKzBi/WQ0Q0dICqufzQbMjipQ=="],
+
     "@types/qs": ["@types/qs@6.14.0", "", {}, "sha512-eOunJqu0K1923aExK6y8p6fsihYEn/BYuQ4g0CxAAgFc4b/ZLN4CrsRZ55srTdqoiLzU2B2evC+apEIxprEzkQ=="],
 
     "@types/range-parser": ["@types/range-parser@1.2.7", "", {}, "sha512-hKormJbkJqzQGhziax5PItDUTMAM9uE2XXQmM37dyd4hVM+5aVl7oVxMVUiVQn2oCQFN/LKCZdvSM0pFRqbSmQ=="],
 
+    "@types/retry": ["@types/retry@0.12.5", "", {}, "sha512-3xSjTp3v03X/lSQLkczaN9UIEwJMoMCA1+Nb5HfbJEQWogdeQIyVtTvxPXDQjZ5zws8rFQfVfRdz03ARihPJgw=="],
+
     "@types/send": ["@types/send@1.2.1", "", { "dependencies": { "@types/node": "*" } }, "sha512-arsCikDvlU99zl1g69TcAB3mzZPpxgw0UQnaHeC1Nwb015xp8bknZv5rIfri9xTOcMuaVgvabfIRA7PSZVuZIQ=="],
 
     "@types/serve-static": ["@types/serve-static@1.15.10", "", { "dependencies": { "@types/http-errors": "*", "@types/node": "*", "@types/send": "<1" } }, "sha512-tRs1dB+g8Itk72rlSI2ZrW6vZg0YrLI81iQSTkMmOqnqCaNr/8Ek4VwWcN5vZgCYWbg/JJSGBlUaYGAOP73qBw=="],
@@ -1091,6 +1097,8 @@
 
     "process-nextick-args": ["process-nextick-args@2.0.1", "", {}, "sha512-3ouUOpQhtgrbOa17J7+uxOTpITYWaGP7/AhoR3+A+/1e9skrzelGi/dXzEYyvbxubEF6Wn2ypscTKiKJFFn1ag=="],
 
+    "proper-lockfile": ["proper-lockfile@4.1.2", "", { "dependencies": { "graceful-fs": "^4.2.4", "retry": "^0.12.0", "signal-exit": "^3.0.2" } }, "sha512-TjNPblN4BwAWMXU8s9AEz4JmQxnD1NNL7bNOY/AKUzyamc379FWASUhc/K1pL2noVb+XmZKLL68cjzLsiOAMaA=="],
+
     "proto-list": ["proto-list@1.2.4", "", {}, "sha512-vtK/94akxsTMhe0/cbfpR+syPuszcuwhqVjJq26CuNDgFGj682oRBXOP5MJpv2r7JtE8MsiepGIqvvOTBwn2vA=="],
 
     "proxy-addr": ["proxy-addr@2.0.7", "", { "dependencies": { "forwarded": "0.2.0", "ipaddr.js": "1.9.1" } }, "sha512-llQsMLSUDUPT44jdrU/O37qlnifitDP+ZwrmmZcoSKyLKvtZxpyV0n2/bD/N4tBAAZ/gJEdZU7KMraoK1+XYAg=="],
@@ -1129,6 +1137,8 @@
 
     "restore-cursor": ["restore-cursor@3.1.0", "", { "dependencies": { "onetime": "^5.1.0", "signal-exit": "^3.0.2" } }, "sha512-l+sSefzHpj5qimhFSE5a8nufZYAM3sBSVMAPtYkmC+4EH2anSGaEMXSD0izRQbu9nfyQ9y5JrVmp7E8oZrUjvA=="],
 
+    "retry": ["retry@0.12.0", "", {}, "sha512-9LkiTwjUh6rT555DtE9rTX+BKByPfrMzEAtnlEtdEwr3Nkffwiihqe2bWADg+OQRjt9gl6ICdmB/ZFDCGAtSow=="],
+
     "rfdc": ["rfdc@1.4.1", "", {}, "sha512-q1b3N5QkRUWUl7iyylaaj3kOpIT0N2i9MqIEQXP73GVsN9cw3fdx8X63cEmWhJGi2PPCF23Ijp7ktmd39rawIA=="],
 
     "rollup": ["rollup@4.53.3", "", { "dependencies": { "@types/estree": "1.0.8" }, "optionalDependencies": { "@rollup/rollup-android-arm-eabi": "4.53.3", "@rollup/rollup-android-arm64": "4.53.3", "@rollup/rollup-darwin-arm64": "4.53.3", "@rollup/rollup-darwin-x64": "4.53.3", "@rollup/rollup-freebsd-arm64": "4.53.3", "@rollup/rollup-freebsd-x64": "4.53.3", "@rollup/rollup-linux-arm-gnueabihf": "4.53.3", "@rollup/rollup-linux-arm-musleabihf": "4.53.3", "@rollup/rollup-linux-arm64-gnu": "4.53.3", "@rollup/rollup-linux-arm64-musl": "4.53.3", "@rollup/rollup-linux-loong64-gnu": "4.53.3", "@rollup/rollup-linux-ppc64-gnu": "4.53.3", "@rollup/rollup-linux-riscv64-gnu": "4.53.3", "@rollup/rollup-linux-riscv64-musl": "4.53.3", "@rollup/rollup-linux-s390x-gnu": "4.53.3", "@rollup/rollup-linux-x64-gnu": "4.53.3", "@rollup/rollup-linux-x64-musl": "4.53.3", "@rollup/rollup-openharmony-arm64": "4.53.3", "@rollup/rollup-win32-arm64-msvc": "4.53.3", "@rollup/rollup-win32-ia32-msvc": "4.53.3", "@rollup/rollup-win32-x64-gnu": "4.53.3", "@rollup/rollup-win32-x64-msvc": "4.53.3", "fsevents": "~2.3.2" }, "bin": { "rollup": "dist/bin/rollup" } }, "sha512-w8GmOxZfBmKknvdXU1sdM9NHcoQejwF/4mNgj2JuEEdRaHwwF12K7e9eXn1nLZ07ad+du76mkVsyeb2rKGllsA=="],