Rebuild the framework with smaller TLS buffers (ADR 0006)

custom_sdkconfig makes pioarduino regenerate the ESP-IDF libraries:
asymmetric TLS buffers (16 KB in, 4 KB out) and dynamic buffers that
free handshake-only data once connected. The rebuild also follows the
board: no PSRAM, 8 MB flash. The project now carries the partition
table the hybrid build needs (identical to the framework's: the app
slots must not move under updates over the air). Generated files are
ignored.

Debug Build, GNSS on, IRC on TLS: 78 KB free and a 59 KB low (M2 began
at 31 KB and 12.6 KB; the floor is 40 KB). The full stress set passes
on it: refused installs over Wi-Fi and from SD, put/get, screenshot,
core dump decode, Probation; under all of it at once, the low is 46 KB.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

default_8MB.csv

@@ -0,0 +1,7 @@
+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x330000,
+app1,     app,  ota_1,   0x340000,0x330000,
+spiffs,   data, spiffs,  0x670000,0x180000,
+coredump, data, coredump,0x7F0000,0x10000,