Filtering + test foundation

[shinagawa-web]

Add live filtering to the TUI so users can narrow captured traffic without restarting the capture.

Scope

• Filter by comm name or path #74

UX sketch

• Keybinding opens a filter input bar at the bottom of the TUI (similar to / in vim or Wireshark's display-filter bar)
• Filter applies instantly to the visible row list; the capture ring buffer is unaffected
• Clearing the filter restores the full list

Out of scope for this issue

• Regex or expression filters — plain equality for now
• Persistent filter presets
• Port filtering — deferred to v2+ (Filter by port #75)

Test foundation (ships in v0.3.0)

• Test strategy — layering, what runs where, conventions #56
• Report abandoned requests when a pair never completes #27
• Expand parser unit tests — status codes, methods, body sizes, malformed input #28
• e2e test suite — real BPF + assertion-driven scenarios #29
• Lifecycle robustness — fd reuse, concurrent connections, parser/pairer Close paths #30
• Integration tests — loader + ringbuf decode against a fixture BPF program #58
• proc unit tests — PID → process-name lookup #59
• Chunked transfer-encoding — parser support + tests #60
• CI — build, vet, and test on every PR #55
• TUI unit tests — model update, key bindings, rendering #76
• dev: add pre-push git hook to enforce tests and 100% coverage #80
• ci: add pre-push hook to enforce test pass and 100% coverage #82
• ci: strengthen golangci-lint — fix QF1001, add linters, fail on warnings #86
• Reference: cicd-sensor's test layout — agent_lifecycle_test.go / correlation_test.go style for BPF + Go integration tests.