feat: tooltips InvestigationView/BruteForce/HeaderFingerprint + fix RouteTracker

- InvestigationView: InfoTip sur Risk Score, JA4 Rotation, TCP Spoof,
  Persistance, UA/CH mismatch, Browser score, JA4 distincts, JA4 rares,
  JA4 Légitimes (baseline)
- BruteForceView: tooltip Params combos, Top JA4, Credential Stuffing, Énumération
- HeaderFingerprintView: tooltip colonnes Hash cluster, Browser Score,
  UA/CH Mismatch %, Sec-Fetch modes
- App.tsx: RouteTracker ignore /investigation/ip/ (route alias)

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

frontend/src/components/HeaderFingerprintView.tsx

@@ -1,6 +1,7 @@
 import { useState, useEffect, useRef } from 'react';
 import { useNavigate } from 'react-router-dom';
 import DataTable, { Column } from './ui/DataTable';
+import { TIPS } from './ui/tooltips';
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
@@ -140,6 +141,7 @@ export function HeaderFingerprintView() {
     {
       key: 'hash',
       label: 'Hash cluster',
+      tooltip: TIPS.hash_cluster,
       sortable: true,
       render: (_, row) => (
         <span>
@@ -158,6 +160,7 @@ export function HeaderFingerprintView() {
     {
       key: 'avg_browser_score',
       label: 'Browser Score',
+      tooltip: TIPS.browser_score,
       sortable: true,
       render: (v) => (
         <div className="flex items-center gap-2">
@@ -171,6 +174,7 @@ export function HeaderFingerprintView() {
     {
       key: 'ua_ch_mismatch_pct',
       label: 'UA/CH Mismatch %',
+      tooltip: TIPS.ua_mismatch,
       sortable: true,
       align: 'right',
       render: (v) => (
@@ -191,6 +195,7 @@ export function HeaderFingerprintView() {
     {
       key: 'top_sec_fetch_modes',
       label: 'Sec-Fetch modes',
+      tooltip: TIPS.sec_fetch,
       sortable: false,
       render: (v) => (
         <div className="flex flex-wrap gap-1">