docs: sync docs with code; fix Makefile modules target

Makefile:
- Add reconciler and ingest to the `modules` target; they were only built
  as side-effects of `make node`, making `make modules` incomplete

planning.md:
- Add 4 missing CLI drivers: discovery_cli, config_cli, protocol_cli,
  query_cli (all existed in code and dev/cli/Makefile but were absent)
- Add header-only utilities table: stream_stats.h, v4l2_fmt.h

README.md:
- Add transport_cli, discovery_cli, config_cli, protocol_cli, query_cli
  to CLI tools list

conventions.md:
- Add ERR_NOT_FOUND to Error_Code enum example
- Replace placeholder Invalid_Error_Detail with actual fields
  (config_line, message) that have been in use since config module
- Add missing error macros: APP_INVALID_ERROR, APP_INVALID_ERROR_MSG,
  APP_NOT_FOUND_ERROR
- Update directory structure: node/ description (was "later"), add web/
  and tools/ entries

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

conventions.md

@@ -77,9 +77,10 @@ Errors are returned as `struct App_Error` values. Functions that can fail return
 /* modules/common/error.h */
 
 typedef enum Error_Code {
-    ERR_NONE    = 0,
-    ERR_SYSCALL = 1,   /* errno is meaningful */
-    ERR_INVALID = 2,
+    ERR_NONE      = 0,
+    ERR_SYSCALL   = 1,   /* errno is meaningful */
+    ERR_INVALID   = 2,
+    ERR_NOT_FOUND = 3,
 } Error_Code;
 
 struct Syscall_Error_Detail {
@@ -87,7 +88,8 @@ struct Syscall_Error_Detail {
 };
 
 struct Invalid_Error_Detail {
-    /* fields added as concrete cases arise */
+    int         config_line;   /* source line number, or 0 if not applicable */
+    const char *message;       /* static string describing what was wrong     */
 };
 
 struct App_Error {
@@ -110,16 +112,17 @@ struct App_Error {
 #define APP_IS_OK(e) \
     ((e).code == ERR_NONE)
 
-#define APP_ERROR(error_code, detail_field, ...) \
-    ((struct App_Error){ \
-        .code   = (error_code), \
-        .file   = __FILE__, \
-        .line   = __LINE__, \
-        .detail = { .detail_field = { __VA_ARGS__ } } \
-    })
-
 #define APP_SYSCALL_ERROR() \
-    APP_ERROR(ERR_SYSCALL, syscall, .err_no = errno)
+    /* sets ERR_SYSCALL + captures errno */
+
+#define APP_INVALID_ERROR() \
+    /* sets ERR_INVALID, no message */
+
+#define APP_INVALID_ERROR_MSG(cfg_line, msg) \
+    /* sets ERR_INVALID with config_line and message */
+
+#define APP_NOT_FOUND_ERROR() \
+    /* sets ERR_NOT_FOUND */
 ```
 
 ### Presentation
@@ -140,11 +143,13 @@ video-setup/
     modules/            - translation units; each has a .c and a Makefile
       common/           - shared types (error, base definitions); no external dependencies
       <module>/
-    node/               - video node entry point and integration (later)
+    node/               - video node binary (source + display sink roles)
   include/              - public headers (.h files)
   dev/                  - development aids; not part of the final deliverable
     cli/                - exploratory CLI drivers, one per module
+    web/                - development web UI (Node.js/Express)
     experiments/        - freeform experiments
+  tools/                - build-time code generators (e.g. gen_font_atlas)
   tests/                - automated tests (later)
   Makefile              - top-level build
 ```