feat: add AWS Bedrock LLM provider via native Converse API (#713)

* feat: add AWS Bedrock LLM provider via native Converse API

* fix: use JSON parsing for tool result error detection instead of brittle substring matching

* refactor: extract duplicated inference config builder into helper function

* fix: address review feedback — safe casts, input validation, and tests

- Safe u32→i32 cast for max_tokens using try_from with clamp
- Remove brittle string-based error detection fallback for tool results
- Validate BEDROCK_CROSS_REGION against allowed values (us/eu/apac/global)
- Validate message list is non-empty before Converse API call
- Log when using default us-east-1 region
- Update llm_backend doc comment to list all backends
- Add tests for build_inference_config and empty message handling

* fix: persist AWS_PROFILE for Bedrock named profile auth

The wizard collected the profile name but only printed a hint to set
it manually. Now it saves to settings and writes AWS_PROFILE to the
bootstrap .env, consistent with how BEDROCK_REGION and other Bedrock
settings are persisted.

* feat: gate AWS Bedrock behind optional `bedrock` feature flag

The AWS SDK dependencies (aws-config, aws-sdk-bedrockruntime,
aws-smithy-types) require cmake and a C compiler to build aws-lc-sys.
Gate them behind an opt-in `bedrock` feature flag so default builds
are unaffected.

Build with: cargo build --features bedrock
All config, settings, and wizard code stays unconditional (no AWS deps)
so users can configure Bedrock even without the feature compiled — they
get a clear error at startup directing them to rebuild.

* fix: address review feedback and adapt Bedrock provider to registry architecture (takeover #345)

- Resolve merge conflicts with main's registry-based provider system
- Add missing cache_creation_input_tokens/cache_read_input_tokens fields
- Add missing content_parts field in test ChatMessage
- Fix string literal type mismatches in wizard env_vars (.to_string())
- Remove non-functional bearer token auth (AWS_BEARER_TOKEN_BEDROCK) from
  wizard and documentation per reviewer feedback from @zmanian and @serrrfirat
- Remove stale BEDROCK_ACCESS_KEY proxy entry from provider table
- Update Bedrock provider to use is_bedrock string check (LlmBackend enum removed)
- Add bedrock_profile fallback from settings in config resolution

[skip-regression-check]

Co-Authored-By: cgorski <[email protected]>
Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: use main's Cargo.lock as base to preserve dependency versions

Regenerating Cargo.lock from scratch caused transitive dependency version
drift that broke the html_to_markdown fixture test in CI.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: bedrock config bugs — spurious warning, alias normalization, profile fallback

- Move is_bedrock check before unknown-backend warning to prevent
  spurious "unknown backend" log for bedrock users
- Normalize backend aliases ("aws", "aws_bedrock") to "bedrock" so
  the provider factory matches correctly
- Add settings.bedrock_profile fallback for AWS_PROFILE, consistent
  with region and cross_region resolution

[skip-regression-check]

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: address Copilot review feedback — bearer token cleanup, stop_sequences, model dedup

- Remove stale bearer token refs from setup README and CHANGELOG
- Remove dead bedrock_api_key secret injection mapping
- Pass stop_sequences through to Bedrock InferenceConfiguration
- Remove "API key" from wizard menu description (bearer token removed)
- Skip duplicate LLM_MODEL write for bedrock backend in wizard
- Fix cargo fmt formatting

[skip-regression-check]

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: address review feedback — async new(), remove LiteLLM entry, wizard fixes

- Remove dead LiteLLM-based bedrock entry from providers.json (native
  Converse API intercepts before registry lookup)
- Make BedrockProvider::new() async to avoid block_in_place panic in
  current_thread runtimes; propagate async to create_llm_provider,
  build_provider_chain, and init_llm
- Document CMake build prerequisite in docs/LLM_PROVIDERS.md
- Clear bedrock_profile when user selects "default credentials" in wizard
- Fix selected_model clearing to match established pattern (conditional
  on provider switch, not unconditional)
- Add regression tests for bedrock model preservation and profile clearing

Addresses review feedback from @zmanian on PR #713.
Streaming support tracked in #741.

[skip-regression-check]

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: address remaining review comments — CLAUDE.md backends, wizard UX

- Add `bedrock` to CLAUDE.md inline backend list (#10)
- Skip full setup re-run when keeping existing Bedrock config (#11)
- Clear stale bedrock_profile on empty named-profile input (#12)
- Add regression test for empty profile clearing

Co-Authored-By: Claude Opus 4.6 <[email protected]>

---------

Co-authored-by: Chris Gorski <[email protected]>
Co-authored-by: cgorski <[email protected]>
Co-authored-by: Claude Opus 4.6 <[email protected]>

providers.json

@@ -295,26 +295,6 @@
       "can_list_models": true
     }
   },
-  {
-    "id": "bedrock",
-    "aliases": [
-      "aws_bedrock",
-      "aws"
-    ],
-    "protocol": "open_ai_completions",
-    "api_key_env": "BEDROCK_ACCESS_KEY",
-    "api_key_required": false,
-    "base_url_env": "BEDROCK_BASE_URL",
-    "model_env": "BEDROCK_MODEL",
-    "default_model": "anthropic.claude-3-5-sonnet-20241022-v2:0",
-    "description": "AWS Bedrock (requires LiteLLM or OpenAI-compatible proxy)",
-    "setup": {
-      "kind": "open_ai_compatible",
-      "secret_name": "llm_bedrock_api_key",
-      "display_name": "AWS Bedrock",
-      "can_list_models": false
-    }
-  },
   {
     "id": "ionet",
     "aliases": [