iter2 step4: wire h265_set_controls to populate EXT_SPS_*_RPS controls

Per Phase 4 plan + Phase 5 review amendments (SPS parse-and-cache,
per-fd gating).

src/h265.c additions:
  - #include <errno.h>, the v4l2-hevc-ext-controls.h, and the
    vendored gst/codecparsers/gsth265parser.h
  - new static helper h265_populate_ext_sps_rps_cache(): walks
    surface_object->source_data for an SPS NAL (nal_unit_type == 33)
    using gst_h265_parser_identify_nalu; if found, calls
    gst_h265_parser_parse_sps_ext (NOT gst_h265_parser_parse_sps —
    the latter discards the per-RPS-entry EXT data we need); maps
    GstH265ShortTermRefPicSet (base) + GstH265ShortTermRefPicSetExt
    (carrying use_delta_flag[16], used_by_curr_pic_flag[16],
    delta_poc_s0_minus1[16], delta_poc_s1_minus1[16]) into the V4L2
    struct arrays; stores on driver_data->hevc_rps_cache_*
  - non-IDR-frame handling: cache holds across frames, so frames
    whose source_data lacks an SPS NAL reuse the previously-parsed
    cached arrays (Phase 5 review item #3)
  - controls[] grows from [5] to [7]; the 2 new entries are appended
    after the standard 5 (SPS/PPS/SLICE_PARAMS/SCALING_MATRIX/
    DECODE_PARAMS), gated by driver_data->has_hevc_ext_sps_rps_rkvdec
    (per-fd probe result from Step 3) + the cache being valid
  - field-by-field mapping mirrors GStreamer's
    gst_v4l2_codec_h265_dec_fill_ext_sps_rps verbatim (the upstream
    reference identified in Phase 0 prior-art survey)

src/request.h additions:
  - struct request_data carries hevc_rps_cache_st (array pointer),
    _st_count, hevc_rps_cache_lt, _lt_count, hevc_rps_cache_valid.
    Single-slot cache (sps_id 0 only; multi-SPS streams would need
    expanding). Stores POST-MAPPED V4L2 structs so request.h doesn't
    need to know GstH265SPS / GstH265SPSEXT types.

Critical interpretation correction (Phase 5 review followup):
GstH265SPS has short_term_ref_pic_set[65] (base) but NOT
short_term_ref_pic_set_ext[]. The EXT array lives on a SEPARATE
GstH265SPSEXT struct accessed via gst_h265_parser_parse_sps_ext.
The 'plain' gst_h265_parser_parse_sps internally calls _ext with a
LOCAL discarded SPSEXT (see gsth265parser.c:2050). Our call must
use the _ext variant directly to keep the EXT data. Caught during
Step 4 first-build error.

Build verified: ninja -C build clean. .so is 759 KB (up from 485 KB
original, 682 KB after Step 2 vendor — the +80 KB is the new helper
+ extension).

iter2 Phase 6 Step 5 (install + reboot + smoke-test) is the F1
falsifier moment: if HEVC stops OOPSing, mechanism confirmed; if it
still OOPSes, loopback Phase 0 with re-opened kernel-agent#11.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/request.h

@@ -38,6 +38,8 @@
 
 #include <linux/videodev2.h>
 
+#include "hevc-ctrls/v4l2-hevc-ext-controls.h"
+
 #define V4L2_REQUEST_STR_VENDOR			"v4l2-request"
 
 #define V4L2_REQUEST_MAX_PROFILES		11
@@ -97,6 +99,29 @@ struct request_data {
 	bool has_hevc_ext_sps_rps_rkvdec;
 	bool has_hevc_ext_sps_rps_hantro;
 
+	/*
+	 * iter2 — cached SPS-derived RPS arrays. SPS NALs only appear in
+	 * source_data on IDR frames; non-IDR frames' h265_set_controls
+	 * reuse the cached arrays so we don't submit zero-filled RPS to
+	 * the kernel (which would re-trigger the OOPS the iter2 fix is
+	 * designed to prevent). Single-slot cache (sps_id 0 only) —
+	 * adequate for the BBB / typical-stream case; multi-SPS streams
+	 * would need expanding to a [16] cache keyed by sps_id.
+	 *
+	 * The cache stores the post-mapped V4L2 control struct arrays
+	 * (not the intermediate GstH265SPS) so request.h doesn't need
+	 * to know about the vendored GStreamer parser types — only the
+	 * V4L2 UAPI structs from hevc-ctrls/v4l2-hevc-ext-controls.h
+	 * included above.
+	 *
+	 * Owned by h265.c; freed at RequestTerminate.
+	 */
+	struct v4l2_ctrl_hevc_ext_sps_st_rps *hevc_rps_cache_st;
+	unsigned int                          hevc_rps_cache_st_count;
+	struct v4l2_ctrl_hevc_ext_sps_lt_rps *hevc_rps_cache_lt;
+	unsigned int                          hevc_rps_cache_lt_count;
+	bool                                  hevc_rps_cache_valid;
+
 	struct video_format *video_format;
 
 	/*