docs(04-01): complete BPF/pcap-reader plan summary and state updates

- Create 04-01-SUMMARY.md for BPF validation, pcap reading, timestamp aggregation
- Update STATE.md: advance plan, record metrics, add decisions, update session
- Update ROADMAP.md: phase 4 progress to 1/2 plans complete
- Mark CAPT-05, CAPT-06 requirements complete in REQUIREMENTS.md

.planning/ROADMAP.md

@@ -76,10 +76,10 @@ Plans:
   1. User can run `netsynth -i eth0 --filter "port 53"` and only DNS traffic is captured and sonified
   2. User can run `netsynth --read capture.pcap -o out.mp3` against an existing pcap file and receive a valid MP3
   3. An invalid BPF filter expression produces a clear error message before any capture begins
-**Plans:** 2 plans
+**Plans:** 1/2 plans executed
 
 Plans:
-- [ ] 04-01-PLAN.md — BPF validation, pcap file reading, timestamp-based aggregation (core library functions)
+- [x] 04-01-PLAN.md — BPF validation, pcap file reading, timestamp-based aggregation (core library functions)
 - [ ] 04-02-PLAN.md — Wire --filter and --read flags into CLI with branching run logic
 
 ## Progress
@@ -92,4 +92,4 @@ Phases execute in numeric order: 1 -> 2 -> 3 -> 4
 | 1. Capture and Classification | 4/4 | Complete   | 2026-03-25 |
 | 2. Audio Synthesis Engine | 3/3 | Complete   | 2026-03-26 |
 | 3. Pipeline Integration and MVP | 2/2 | Complete   | 2026-03-26 |
-| 4. Power User Features | 0/2 | Not started | - |
+| 4. Power User Features | 1/2 | In Progress|  |