feat: extract shared infrastructure from shared_lib

Phase 1-3 of decoupling plan:
- Shared DB, models, infrastructure, browser, config, utils
- Event infrastructure (domain_events outbox, bus, processor)
- Structured logging
- Generic container concept (container_type/container_id)
- Alembic migrations for all schema changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

browser/app/utils/__init__.py

@@ -0,0 +1,12 @@
+from .parse import (
+  parse_time,
+  parse_cost,
+  parse_dt
+)
+from .utils import (
+  current_route_relative_path,
+  current_url_without_page,
+  vary,
+)
+
+from .utc import utcnow

browser/app/utils/htmx.py

@@ -0,0 +1,46 @@
+"""HTMX utilities for detecting and handling HTMX requests."""
+
+from quart import request
+
+
+def is_htmx_request() -> bool:
+    """
+    Check if the current request is an HTMX request.
+
+    Returns:
+        bool: True if HX-Request header is present and true
+    """
+    return request.headers.get("HX-Request", "").lower() == "true"
+
+
+def get_htmx_target() -> str | None:
+    """
+    Get the target element ID from HTMX request headers.
+
+    Returns:
+        str | None: Target element ID or None
+    """
+    return request.headers.get("HX-Target")
+
+
+def get_htmx_trigger() -> str | None:
+    """
+    Get the trigger element ID from HTMX request headers.
+
+    Returns:
+        str | None: Trigger element ID or None
+    """
+    return request.headers.get("HX-Trigger")
+
+
+def should_return_fragment() -> bool:
+    """
+    Determine if we should return a fragment vs full page.
+
+    For HTMX requests, return fragment.
+    For normal requests, return full page.
+
+    Returns:
+        bool: True if fragment should be returned
+    """
+    return is_htmx_request()

browser/app/utils/parse.py

@@ -0,0 +1,36 @@
+from datetime import datetime, timezone
+
+def parse_time(val: str | None):
+    if not val:
+        return None
+    try:
+        h,m = val.split(':', 1)
+        from datetime import time
+        return time(int(h), int(m))
+    except Exception:
+        return None
+
+def parse_cost(val: str | None):
+    if not val:
+        return None
+    try:
+        return float(val)
+    except Exception:
+        return None
+
+    if not val:
+        return None
+    dt = datetime.fromisoformat(val)
+    # make TZ-aware (assume local if naive; convert to UTC)
+    if dt.tzinfo is None:
+        dt = dt.replace(tzinfo=timezone.utc)
+    return dt
+
+def parse_dt(val: str | None) -> datetime | None:
+    if not val:
+        return None
+    dt = datetime.fromisoformat(val)
+    if dt.tzinfo is None:
+        dt = dt.replace(tzinfo=timezone.utc)
+    return dt
+

browser/app/utils/utc.py

@@ -0,0 +1,6 @@
+from datetime import datetime, timezone
+
+
+def utcnow() -> datetime:
+    return datetime.now(timezone.utc)
+

browser/app/utils/utils.py

@@ -0,0 +1,51 @@
+from quart import (
+  Response,
+  request,
+  g,
+)
+from shared.utils import host_url
+from urllib.parse import urlencode
+
+def current_route_relative_path() -> str:
+    """
+    Returns the current request path relative to the app's mount point (script_root).
+    """
+
+    (request.script_root or "").rstrip("/")
+    path = request.path  # excludes query string
+
+
+
+    if g.root and path.startswith(f"/{g.root}"):
+        rel = path[len(g.root+1):]
+        return rel if rel.startswith("/") else "/" + rel
+    return path  # app at /
+
+
+def current_url_without_page() -> str:
+    """
+    Build current URL (host+path+qs) but with ?page= removed.
+    Used for Hx-Push-Url.
+    """
+    base = host_url(current_route_relative_path())
+
+    params = request.args.to_dict(flat=False)  # keep multivals
+    params.pop("page", None)
+    qs = urlencode(params, doseq=True)
+
+    return f"{base}?{qs}" if qs else base
+
+def vary(resp: Response) -> Response:
+    """
+    Ensure caches/CDNs vary on HX headers so htmx/non-htmx versions don't get mixed.
+    """
+    v = resp.headers.get("Vary", "")
+    parts = [p.strip() for p in v.split(",") if p.strip()]
+    for h in ("HX-Request", "X-Origin"):
+        if h not in parts:
+            parts.append(h)
+    if parts:
+        resp.headers["Vary"] = ", ".join(parts)
+    return resp
+
+