espressif: freeze the env-collector's libraries on the 13 boards it targets

The ESP-NOW / WiFi / BLE environmental collector ships ~20 libraries in
lib/. On a board without PSRAM that is the difference between running and
not. Measured on a Feather ESP32-S3 No PSRAM (2026-09-13), with the
application itself already cross-compiled to .mpy:

  * BLE + ESP-NOW + softAP all come up, and then `import datastore` dies
    with `MemoryError: memory allocation failed, allocating 158 bytes`;
  * with BLE off it gets as far as building the eInk dashboard and the SD
    mount fails for want of 832 bytes, with 15.9 KB free.

Cross-compiling the application removes the on-device *compiler* peak,
which is what made the C6 unbootable, but not the resident bytecode.
Freezing does: a frozen module executes in place from flash and never
occupies heap at all.

So this adds FROZEN_MPY_DIRS for the libraries the project actually uses,
to the 13 espressif boards it targets -- the same 13 the custom-build
workflow has been dispatched for.

The list lives in ports/espressif/envhub_frozen.mk and each board gets one
`include` line rather than twenty `FROZEN_MPY_DIRS +=` lines. These are
upstream-shared board files: one line of divergence rebases far more
quietly than twenty, and there is one place to edit when the library set
moves.

Nine libraries were not yet in frozen/ and are added as submodules:
IL0373, JD79667, MAX1704x, NTP, SCD4X, SCD30, SEN6x, PCF8523, DS1307.
The other thirteen were already there.

Deliberately NOT frozen:
  * adafruit_pixelbuf -- already a built-in C module.
  * sensirion_i2c_driver / sensirion_i2c_sen5x -- from a third-party
    circup bundle rather than a library repo, and node_sensors.py carries
    a minimal built-in SEN5x driver for boards without them.
  * PCF85063A -- no Adafruit library exists; the project drives that chip
    directly from its own extrtc.py.

Size: ~162 KB of frozen bytecode from 621 KB of source, uniform across
all 13. That is comfortable on the 8 MB and 16 MB boards and is the open
question on the 4 MB ones (qtpy_esp32s3_4mbflash_2mbpsram,
feather_huzzah32, feather_esp32s3_tft, feather_esp32s3_reverse_tft,
feather_esp32s3_4mbflash_2mbpsram, feather_esp32c6_4mbflash_nopsram) --
CI is the arbiter, and if one overflows the fix is to split the list
rather than to shrink it everywhere.

NOTE for whoever deploys against these builds: `sys.path` puts `/lib`
ahead of `.frozen`, so a copy left in lib/ SHADOWS the frozen one and the
board pays the RAM anyway. Deleting lib/ is what collects the benefit --
the same trap as leaving a .py beside a .mpy.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: tyeth

.gitmodules

@@ -430,3 +430,30 @@
 [submodule "frozen/Adafruit_CircuitPython_TAS2505"]
 	path = frozen/Adafruit_CircuitPython_TAS2505
 	url = https://github.com/adafruit/Adafruit_CircuitPython_TAS2505.git
+[submodule "frozen/Adafruit_CircuitPython_IL0373"]
+	path = frozen/Adafruit_CircuitPython_IL0373
+	url = https://github.com/adafruit/Adafruit_CircuitPython_IL0373.git
+[submodule "frozen/Adafruit_CircuitPython_JD79667"]
+	path = frozen/Adafruit_CircuitPython_JD79667
+	url = https://github.com/adafruit/Adafruit_CircuitPython_JD79667.git
+[submodule "frozen/Adafruit_CircuitPython_MAX1704x"]
+	path = frozen/Adafruit_CircuitPython_MAX1704x
+	url = https://github.com/adafruit/Adafruit_CircuitPython_MAX1704x.git
+[submodule "frozen/Adafruit_CircuitPython_NTP"]
+	path = frozen/Adafruit_CircuitPython_NTP
+	url = https://github.com/adafruit/Adafruit_CircuitPython_NTP.git
+[submodule "frozen/Adafruit_CircuitPython_SCD4X"]
+	path = frozen/Adafruit_CircuitPython_SCD4X
+	url = https://github.com/adafruit/Adafruit_CircuitPython_SCD4X.git
+[submodule "frozen/Adafruit_CircuitPython_SCD30"]
+	path = frozen/Adafruit_CircuitPython_SCD30
+	url = https://github.com/adafruit/Adafruit_CircuitPython_SCD30.git
+[submodule "frozen/Adafruit_CircuitPython_SEN6x"]
+	path = frozen/Adafruit_CircuitPython_SEN6x
+	url = https://github.com/adafruit/Adafruit_CircuitPython_SEN6x.git
+[submodule "frozen/Adafruit_CircuitPython_PCF8523"]
+	path = frozen/Adafruit_CircuitPython_PCF8523
+	url = https://github.com/adafruit/Adafruit_CircuitPython_PCF8523.git
+[submodule "frozen/Adafruit_CircuitPython_DS1307"]
+	path = frozen/Adafruit_CircuitPython_DS1307
+	url = https://github.com/adafruit/Adafruit_CircuitPython_DS1307.git