feat(docker): container detail page + lifecycle timeline (milestone 77 #942)

New /plugins/docker/container/<host_id>/<name> detail page (v1 quality):
status/health badge, uptime, CPU/mem, restart count, last exit code (+OOM),
net + block I/O (humanised), image/compose/swarm-service/node/ports, a
range-toggled CPU/mem history graph (HTMX fragment reusing the time-range
selector), and a lifecycle timeline rendered from docker_events (glyph+colour
per event kind). Not-found and empty-history/empty-timeline states included.
Container names in the main list and the per-host hub panel now link to it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Jg27rgypiW2efULXJDtMC

plugins/docker/routes.py

@@ -10,11 +10,25 @@ from steward.auth.middleware import require_role
 from steward.models.users import UserRole
 from steward.models.hosts import Host
 from steward.core.time_range import parse_range, DEFAULT_RANGE
-from .models import DockerContainer, DockerMetric
+from .models import DockerContainer, DockerEvent, DockerMetric
 
 docker_bp = Blueprint("docker", __name__, template_folder="templates")
 
 
+def _human_bytes(n: int | None) -> str:
+    """Compact binary size string (e.g. '1.4 GiB', '512 MiB', '0 B')."""
+    if n is None:
+        return "—"
+    size = float(n)
+    for unit in ("B", "KiB", "MiB", "GiB", "TiB"):
+        if abs(size) < 1024.0 or unit == "TiB":
+            if unit == "B":
+                return f"{int(size)} {unit}"
+            return f"{size:.1f} {unit}"
+        size /= 1024.0
+    return f"{size:.1f} TiB"
+
+
 def _human_uptime(started_at: datetime | None) -> str | None:
     """Compact 'how long running' string (e.g. '3d 4h', '5h 12m', '8m')."""
     if started_at is None:
@@ -258,3 +272,72 @@ async def host_panel(host_id: str):
         running=running,
         stopped=len(containers) - running,
     )
+
+
+# Glyph + colour per lifecycle event, so the timeline reads at a glance.
+_EVENT_STYLE = {
+    "start":         ("▲", "var(--green)"),
+    "stop":          ("■", "var(--text-muted)"),
+    "die":           ("✕", "var(--red)"),
+    "oom":           ("☠", "var(--red)"),
+    "health_change": ("◐", "var(--orange)"),
+}
+
+
+@docker_bp.get("/container/<host_id>/<name>")
+@require_role(UserRole.viewer)
+async def container_detail(host_id: str, name: str):
+    """Full detail page for one container: facts, resource history, lifecycle."""
+    async with current_app.db_sessionmaker() as db:
+        c = await db.get(DockerContainer, (host_id, name))
+        host = await db.get(Host, host_id)
+        events = []
+        if c is not None:
+            events = list((await db.execute(
+                select(DockerEvent)
+                .where(DockerEvent.host_id == host_id)
+                .where(DockerEvent.container_name == name)
+                .order_by(DockerEvent.at.desc())
+                .limit(50)
+            )).scalars())
+
+    if c is None:
+        return await render_template(
+            "docker/container_detail.html",
+            container=None, host_id=host_id, name=name,
+        ), 404
+
+    return await render_template(
+        "docker/container_detail.html",
+        container=c,
+        host=host,
+        host_id=host_id,
+        name=name,
+        ports=json.loads(c.ports_json) if c.ports_json else [],
+        uptime=_human_uptime(c.started_at) if c.status == "running" else None,
+        net_rx=_human_bytes(c.net_rx_bytes), net_tx=_human_bytes(c.net_tx_bytes),
+        blk_read=_human_bytes(c.blk_read_bytes), blk_write=_human_bytes(c.blk_write_bytes),
+        events=[
+            {"event": e.event, "detail": e.detail, "at": e.at,
+             "glyph": _EVENT_STYLE.get(e.event, ("•", "var(--text-muted)"))[0],
+             "colour": _EVENT_STYLE.get(e.event, ("•", "var(--text-muted)"))[1]}
+            for e in events
+        ],
+        current_range=request.args.get("range", DEFAULT_RANGE),
+    )
+
+
+@docker_bp.get("/container/<host_id>/<name>/history")
+@require_role(UserRole.viewer)
+async def container_history(host_id: str, name: str):
+    """HTMX fragment: CPU + memory sparklines for the selected time range."""
+    since, range_key = parse_range(request.args.get("range"))
+    async with current_app.db_sessionmaker() as db:
+        cpu_hist, mem_hist = await _container_history(db, host_id, name, since)
+    return await render_template(
+        "docker/_container_history.html",
+        sparkline_cpu=_sparkline(cpu_hist, width=320, height=48),
+        sparkline_mem=_sparkline(mem_hist, width=320, height=48),
+        have_data=len(cpu_hist) >= 2,
+        range_key=range_key,
+    )