feat: help modal, comprehensive intelligence, fix right-side position

Position fix:
- Remove _chat.css @import from main.css (was overriding with old
  left:2rem cached version). Chat CSS now loaded only via head-styles.
- Button confirmed at right:2rem, bottom:6rem (above back-to-top)

Help modal:
- New chat-help-modal.html using same <dialog> pattern as shortcuts
- 6 organized categories: Experience, Technologies, Projects,
  Education, Skills, How it works
- Bilingual EN/ES with example questions per category
- ? button in header opens modal via commandfor/show-modal
- Removed inline help card (modal replaces it)

Intelligence:
- Comprehensive query strategy for 8 question types
- Technology queries always use cross-section search
- Company queries use experience without filter for full listing
- Agent knows CV site is built with Go/HTMX (bonus context)
- Skills report proficiency levels when technology found

static/css/04-interactive/_chat.css

@@ -117,63 +117,6 @@
     color: #fff;
 }
 
-/* ==========================================================================
-   Help / Onboarding Card
-   ========================================================================== */
-
-.chat-help-card {
-    display: none;
-    flex-direction: column;
-    align-items: center;
-    gap: 8px;
-    padding: 14px 16px;
-    margin: 10px;
-    background: var(--paper-secondary-bg, #f5f5f5);
-    border: 1px solid var(--border-light, #e0e0e0);
-    border-radius: 6px;
-    text-align: center;
-    animation: helpFadeIn 0.2s ease;
-}
-
-.chat-help-card.visible {
-    display: flex;
-}
-
-@keyframes helpFadeIn {
-    from { opacity: 0; transform: translateY(-4px); }
-    to   { opacity: 1; transform: translateY(0); }
-}
-
-.chat-help-icon {
-    font-size: 1.6rem;
-    color: var(--accent-blue, #0066cc);
-    line-height: 1;
-}
-
-.chat-help-text {
-    font-size: 0.78rem;
-    line-height: 1.5;
-    color: var(--text-muted, #666666);
-    margin: 0;
-}
-
-.chat-help-dismiss {
-    background: var(--black-bar, #2b2b2b);
-    color: #fff;
-    border: none;
-    border-radius: 4px;
-    padding: 4px 14px;
-    font-size: 0.72rem;
-    font-weight: 600;
-    cursor: pointer;
-    transition: background 0.2s;
-    font-family: 'Quicksand', sans-serif;
-}
-
-.chat-help-dismiss:hover {
-    background: var(--accent-blue, #0066cc);
-}
-
 /* ==========================================================================
    Messages Area
    ========================================================================== */
@@ -418,15 +361,6 @@
     color: #d0d0d0;
 }
 
-.theme-clean .chat-help-card {
-    background: #2a2a2a;
-    border-color: #333333;
-}
-
-.theme-clean .chat-help-text {
-    color: #999999;
-}
-
 .theme-clean .chat-suggestions {
     border-top-color: #333333;
 }