docs: add execution blueprint and task files for plan 12

Add execution blueprint section to the plan and individual task
files for mutmut config/CI setup and killing surviving mutants
across protocol, client, auth, and b2c_login modules.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: deviantintegral

.ai/task-manager/plans/12--mutation-testing-expansion/plan-12--mutation-testing-expansion.md

@@ -126,3 +126,16 @@ Update the mutation test step in `.github/workflows/ci.yml` to run mutmut on all
 - The `mutants/` directory is mutmut v3's working directory and should be gitignored.
 - TUI modules and `cli.py` are intentionally excluded from this plan. They can be added later if desired.
 - Some surviving mutants will be equivalent (semantically identical to the original). These should be documented rather than chased with brittle tests.
+
+---
+
+## Execution Blueprint
+
+### ✅ Phase 1: Configuration Setup
+- ✔️ Task 01: Setup mutmut configuration, .gitignore, and CI update (`01--mutmut-config-and-ci.md`)
+
+### Phase 2: Kill Surviving Mutants (parallel)
+- Task 02: Kill surviving mutants in protocol.py (`02--kill-protocol-mutants.md`)
+- Task 03: Kill surviving mutants in client.py (`03--kill-client-mutants.md`)
+- Task 04: Kill surviving mutants in auth.py (`04--kill-auth-mutants.md`)
+- Task 05: Kill surviving mutants in b2c_login.py (`05--kill-b2c-mutants.md`)

.ai/task-manager/plans/12--mutation-testing-expansion/tasks/01--mutmut-config-and-ci.md

@@ -0,0 +1,27 @@
+---
+id: 1
+group: "mutation-testing-expansion"
+dependencies: []
+status: "completed"
+created: 2026-02-25
+skills:
+  - "ci-config"
+---
+# Setup mutmut configuration, .gitignore, and CI update
+
+## Objective
+Create `setup.cfg` with mutmut configuration, update `.gitignore` with `mutants/`, and expand CI mutation testing to all 4 core modules.
+
+## Acceptance Criteria
+- [ ] `setup.cfg` exists with `[mutmut]` section containing `paths_to_mutate` and `also_copy`
+- [ ] `.gitignore` includes `mutants/` and replaces stale `.mutmut-cache/` entry
+- [ ] CI workflow runs mutmut on protocol.py, client.py, auth.py, and b2c_login.py
+- [ ] `uv run mutmut run --paths-to-mutate=src/flameconnect/auth.py --no-progress` works locally
+
+## Technical Requirements
+- Create `setup.cfg` with `[mutmut]` section
+- Update `.gitignore`: add `mutants/`, remove `.mutmut-cache/`
+- Update `.github/workflows/ci.yml` mutation test step to run on all 4 modules
+
+## Output Artifacts
+- `setup.cfg` (new), `.gitignore` (updated), `.github/workflows/ci.yml` (updated)

.ai/task-manager/plans/12--mutation-testing-expansion/tasks/02--kill-protocol-mutants.md

@@ -0,0 +1,28 @@
+---
+id: 2
+group: "mutation-testing-expansion"
+dependencies: [1]
+status: "pending"
+created: 2026-02-25
+skills:
+  - "python-testing"
+  - "mutation-testing"
+---
+# Kill surviving mutants in protocol.py
+
+## Objective
+Write targeted tests to raise protocol.py mutation score from 62% to ≥90% by killing the 266 surviving mutants.
+
+## Acceptance Criteria
+- [ ] New tests added to `tests/test_protocol.py`
+- [ ] Mutation score ≥90% verified by `uv run mutmut run --paths-to-mutate=src/flameconnect/protocol.py --no-progress`
+- [ ] All tests pass
+- [ ] No files in `src/` modified
+
+## Technical Requirements
+- Run mutmut to identify surviving mutants
+- Analyze each surviving mutant to understand what assertion is missing
+- Write targeted test assertions for: individual decoded field values, byte-level encoding correctness, constant values, boundary conditions
+
+## Output Artifacts
+- Updated `tests/test_protocol.py` with additional test assertions

.ai/task-manager/plans/12--mutation-testing-expansion/tasks/03--kill-client-mutants.md

@@ -0,0 +1,27 @@
+---
+id: 3
+group: "mutation-testing-expansion"
+dependencies: [1]
+status: "pending"
+created: 2026-02-25
+skills:
+  - "python-testing"
+  - "mutation-testing"
+---
+# Kill surviving mutants in client.py
+
+## Objective
+Write targeted tests to raise client.py mutation score from 64% to ≥90% by killing the 116 surviving mutants.
+
+## Acceptance Criteria
+- [ ] New tests added to `tests/test_client.py`
+- [ ] Mutation score ≥90% verified by mutmut
+- [ ] All tests pass
+- [ ] No files in `src/` modified
+
+## Technical Requirements
+- Run mutmut to identify surviving mutants
+- Write tests asserting on specific URL paths, request payloads, HTTP methods, headers, and parsed response fields
+
+## Output Artifacts
+- Updated `tests/test_client.py` with additional test assertions

.ai/task-manager/plans/12--mutation-testing-expansion/tasks/04--kill-auth-mutants.md

@@ -0,0 +1,27 @@
+---
+id: 4
+group: "mutation-testing-expansion"
+dependencies: [1]
+status: "pending"
+created: 2026-02-25
+skills:
+  - "python-testing"
+  - "mutation-testing"
+---
+# Kill surviving mutants in auth.py
+
+## Objective
+Establish mutation testing on auth.py with ≥90% kill rate.
+
+## Acceptance Criteria
+- [ ] New tests added to `tests/test_auth.py`
+- [ ] Mutation score ≥90% verified by mutmut
+- [ ] All tests pass
+- [ ] No files in `src/` modified
+
+## Technical Requirements
+- Run mutmut on auth.py to identify all surviving mutants
+- Write targeted tests for authentication logic: token acquisition, cache handling, error paths
+
+## Output Artifacts
+- Updated `tests/test_auth.py` with additional test assertions

.ai/task-manager/plans/12--mutation-testing-expansion/tasks/05--kill-b2c-mutants.md

@@ -0,0 +1,27 @@
+---
+id: 5
+group: "mutation-testing-expansion"
+dependencies: [1]
+status: "pending"
+created: 2026-02-25
+skills:
+  - "python-testing"
+  - "mutation-testing"
+---
+# Kill surviving mutants in b2c_login.py
+
+## Objective
+Establish mutation testing on b2c_login.py with ≥90% kill rate.
+
+## Acceptance Criteria
+- [ ] New tests added to `tests/test_b2c_login.py`
+- [ ] Mutation score ≥90% verified by mutmut
+- [ ] All tests pass
+- [ ] No files in `src/` modified
+
+## Technical Requirements
+- Run mutmut on b2c_login.py to identify all surviving mutants
+- Write targeted tests for B2C login flow: HTTP redirect handling, HTML parsing, token exchange, error paths
+
+## Output Artifacts
+- Updated `tests/test_b2c_login.py` with additional test assertions