[AZ-640] Bootstrap Rust workspace, CI/Docker, observability scaffold

Lands the first task of the implementation epic AZ-626: a cargo workspace
with 14 crates (shared + autopilot binary + 12 component crates), a
multi-stage Dockerfile + dev/test compose stacks, a Woodpecker CI pipeline,
the on-airframe systemd unit with flight-gate wiring, three environment
TOML configs, and the canonical entity catalogue from data_model.md as
`shared::models`.

Per-AC verification (full detail in
_docs/03_implementation/batch_01_cycle1_report.md):

- AC-1 cargo check --workspace clean
- AC-2 cargo test --workspace passes; per-crate it_compiles() <0.01 s
- AC-6 cargo build/test --no-default-features clean; VlmClient default
       impl returns VlmAssessment::disabled()
- AC-9 tracing-subscriber emits JSON logs with ts/level/target/fields
- AC-10 runtime::ensure_state_directories creates mapobjects/, audit/,
        pending_pushes/ under storage.state_dir

Deferred to external infra (artifacts written, verification re-runs in CI
and in downstream tasks):
- AC-3 Woodpecker runner; CI yml in place
- AC-4 docker-compose mocks land with AZ-660/AZ-644/AZ-675
- AC-5 SITL conformance lands with AZ-641/AZ-648/AZ-652
- AC-7 aarch64 cross-compile via cargo-zigbuild stage
- AC-8 systemd unit (Linux + systemd host)

Layering invariants from module-layout.md hold: shared (L1) imports
nothing; Layer 2 actor crates import only shared; Layer 3 coordinators
(operator_bridge, mission_executor) import only their documented Layer 2
deps; Layer 4 (scan_controller) imports its documented Layer 2 + Layer 3
deps; the autopilot binary (L5) is the only consumer of every component.

cargo fmt --all --check + cargo clippy --all-targets -- -D warnings both
clean. Jira AZ-640 transitioned to In Progress at the start of this batch;
the matching In Testing transition follows this commit.

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/frame_ingest/src/lib.rs

@@ -0,0 +1,59 @@
+//! `frame_ingest` — RTSP pull + decode + timestamp.
+//!
+//! Real implementation lands in:
+//! - AZ-657 `frame_ingest_rtsp_session`
+//! - AZ-658 `frame_ingest_decoder`
+//! - AZ-659 `frame_ingest_publisher`
+
+use tokio::sync::broadcast;
+
+use shared::health::ComponentHealth;
+use shared::models::frame::Frame;
+
+const NAME: &str = "frame_ingest";
+
+pub struct FrameIngest {
+    tx: broadcast::Sender<Frame>,
+}
+
+impl FrameIngest {
+    pub fn new(channel_capacity: usize) -> Self {
+        let (tx, _rx) = broadcast::channel(channel_capacity);
+        Self { tx }
+    }
+
+    pub fn handle(&self) -> FrameIngestHandle {
+        FrameIngestHandle {
+            tx: self.tx.clone(),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct FrameIngestHandle {
+    tx: broadcast::Sender<Frame>,
+}
+
+impl FrameIngestHandle {
+    /// Subscribe to the frame stream. Consumers receive every frame after they
+    /// subscribed; back-pressure is implemented via broadcast channel lag (see
+    /// AZ-659 for the slow-consumer policy).
+    pub fn subscribe(&self) -> broadcast::Receiver<Frame> {
+        self.tx.subscribe()
+    }
+
+    pub fn health(&self) -> ComponentHealth {
+        ComponentHealth::disabled(NAME)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_compiles() {
+        let h = FrameIngest::new(8).handle();
+        assert_eq!(h.health().level, shared::health::HealthLevel::Disabled);
+    }
+}