docs(06-01): complete config package plan summary and state updates

- 06-01-SUMMARY.md: TOML config loader with partial merge and unknown-key detection
- STATE.md: advanced to Plan 1 complete, added Phase 06-01 decisions and metrics
- ROADMAP.md: updated Phase 6 plan progress (1/2 plans complete)
- REQUIREMENTS.md: marked CFG-01, CFG-02, CFG-04, CFG-05 complete

.planning/ROADMAP.md

@@ -53,10 +53,10 @@ Plans:
   3. User passes `--config /path/to/custom.toml` and the tool uses that file; if the file does not exist, the tool exits with a clear error before capture begins
   4. User types `frequncy = 440` in their config file and the tool exits at startup with an error naming `frequncy` as an unrecognized key
   5. User sets waveform for one class in TOML and leaves all other classes at their defaults — the unspecified classes are unchanged
-**Plans:** 2 plans
+**Plans:** 1/2 plans executed
 
 Plans:
-- [ ] 06-01-PLAN.md — Config package: TOML load, validate, merge with TDD (config/config.go, config/config_test.go)
+- [x] 06-01-PLAN.md — Config package: TOML load, validate, merge with TDD (config/config.go, config/config_test.go)
 - [ ] 06-02-PLAN.md — CLI wiring: --config flag, RunSynthesis signature change, main.go integration
 
 ### Phase 7: Custom Rules and Print-Config
@@ -79,5 +79,5 @@ Plans:
 | 3. Pipeline Integration and MVP | v1.0 | 2/2 | Complete | 2026-03-26 |
 | 4. Power User Features | v1.0 | 2/2 | Complete | 2026-03-26 |
 | 5. Waveform Types and Bank Decoupling | v1.1 | 2/2 | Complete   | 2026-03-26 |
-| 6. Config Package and Sound Overrides | v1.1 | 0/2 | Planning complete | - |
+| 6. Config Package and Sound Overrides | v1.1 | 1/2 | In Progress|  |
 | 7. Custom Rules and Print-Config | v1.1 | 0/? | Not started | - |