feat: HTTP/2 passive fingerprinting with individual SETTINGS fields

Complete implementation of HTTP/2 passive fingerprinting per thesis §2.5.3:

mod-reqin-log (C module):
- Replace connection-level filter with ap_hook_process_connection (APR_HOOK_FIRST)
  to capture H2 preface before mod_http2 takes over the connection
- AP_MODE_SPECULATIVE read of 512 bytes from c->input_filters
- Parse SETTINGS, WINDOW_UPDATE, PRIORITY flags, pseudo-header order
- Output individual SETTINGS params as separate JSON fields (IDs 1-6, 8)
- Read H2 notes from c1 (master connection) for mod_http2 secondary conns
- Fix header_order_signature JSON length bug (26→strlen)

ClickHouse schema:
- Add 8 new columns to http_logs: h2_has_priority, h2_header_table_size,
  h2_enable_push, h2_max_concurrent_streams, h2_initial_window_size,
  h2_max_frame_size, h2_max_header_list_size, h2_enable_connect_protocol
- Use Int32/Int64 with DEFAULT -1 to distinguish absent vs zero
- Update mv_http_logs to extract individual fields via JSONHas/JSONExtractInt
- Migration 04_http2_fields.sql updated for existing deployments

Correlator:
- Accept both timestamp_ns and timestamp field names (backward compat)

Integration:
- Enable HTTP/2 in Apache: Protocols h2 http/1.1 in httpd-integration.conf

Validated end-to-end via Playwright: H2 curl traffic → mod-reqin-log →
correlator → ClickHouse with all 12 H2 columns populated correctly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/services/dashboard.md

@@ -1,6 +1,6 @@
 # Dashboard
 
-Application web SOC (Security Operations Center) construite avec **FastAPI + Jinja2 + htmx**,
+Application web SOC (Security Operations Center) construite avec **FastAPI + Jinja2 + ECharts**,
 offrant la visualisation en temps réel, l'investigation et l'analyse des détections de bots
 générées par le [bot-detector](bot-detector.md). Interroge ClickHouse sur deux bases de données
 (`ja4_processing` et `ja4_logs`).
@@ -13,8 +13,8 @@ générées par le [bot-detector](bot-detector.md). Interroge ClickHouse sur deu
 |-----------|-------------|
 | Backend | Python 3.11 + FastAPI |
 | Templates | Jinja2 (rendu côté serveur) |
-| Interactions dynamiques | htmx (mises à jour partielles via JSON API) |
-| Graphiques | Chart.js + ECharts |
+| Interactions dynamiques | Vanilla `fetch()` (appels JSON API avec rechargement partiel côté JS) |
+| Graphiques | ECharts 5.5 (CDN) |
 | Style | Tailwind CSS (CDN) |
 | Base de données | ClickHouse via `clickhouse-connect` (client propre, **PAS** `ja4_common`) |
 | Documentation API | Swagger UI (`/docs`) + OpenAPI JSON (`/openapi.json`) |