docs: write CLI docs for all 12 previously undocumented tools

Add docs/cli/ entries for:
  transport_cli, discovery_cli, config_cli, protocol_cli, query_cli,
  test_image_cli, xorg_cli, v4l2_view_cli, stream_send_cli,
  stream_recv_cli, reconciler_cli, controller_cli

Each doc covers: description, build instructions, full usage with all
options and defaults, example output, and a relationship note pointing
to related tools. controller_cli includes the display control IDs table
and notes its temporary status.

README.md: convert all CLI tool entries to links.

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

docs/cli/query_cli.md

@@ -0,0 +1,64 @@
+# query_cli
+
+An integration smoke test that combines discovery and protocol. Waits for a video node to appear on the local network, then sends an ENUM_DEVICES query and prints the results. Optionally enumerates controls on a specific device.
+
+---
+
+## Build
+
+From the repository root:
+
+```sh
+make cli
+```
+
+The binary is placed in `build/cli/`.
+
+---
+
+## Usage
+
+```sh
+./query_cli [--timeout ms] [--controls device_index]
+```
+
+| Option | Default | Description |
+|---|---|---|
+| `--timeout ms` | `5000` | How long to wait for a node to appear (milliseconds) |
+| `--controls idx` | — | After enumeration, also query controls for this device index |
+
+Example — query the first node found within 5 s:
+
+```sh
+./query_cli
+```
+
+Example output:
+
+```
+discovered: camera:0  192.168.1.42:8000
+querying devices...
+  media  /dev/media0  driver=unicam  model=unicam  bus=platform:fe801000.csi  (1 video node)
+    [0] video  /dev/video0  entity=unicam-image  type=0x00010001  caps=[video-capture]  [capture]
+  [1] standalone  /dev/video1  card=USB Camera
+```
+
+Example with controls:
+
+```sh
+./query_cli --controls 1
+```
+
+```
+  ctrl  id=0x00980900  Brightness  int  min=0  max=255  step=1  default=128  current=127
+  ctrl  id=0x00980901  Contrast    int  min=0  max=255  step=1  default=128  current=128
+  ...
+```
+
+---
+
+## Relationship to the Video Routing System
+
+`query_cli` is an end-to-end integration test: it exercises discovery, transport, and protocol in one shot. It is the simplest way to verify that a node is reachable and responding correctly to control requests before using `controller_cli` for full interaction.
+
+See also: [`discovery_cli.md`](discovery_cli.md), [`controller_cli.md`](controller_cli.md).