Reorganize task categories from opaque a/b to descriptive names

Replace category_a/category_b directories with algorithm, pipeline,
environment, filesystem, and process. Add separate mode field (solve/convert)
to decouple orchestration from capability grouping. Add per-category
summary and questionnaire breakdowns to both terminal report and HTML export.

tasks/environment/env_config.toml

@@ -0,0 +1,33 @@
+name = "env_config"
+category = "environment"
+mode = "solve"
+description = """
+Read a config format from stdin where each line is "KEY=VALUE".
+For each line, set an environment variable with that key and value.
+After processing all lines, run the command `env` and print only the variables
+that were set from the input, sorted alphabetically by key, in "KEY=VALUE" format.
+
+You must actually set these as environment variables and retrieve them back
+(not just echo the input).
+"""
+
+[[test_cases]]
+stdin = """APP_NAME=myapp
+APP_PORT=8080
+APP_DEBUG=true"""
+expected_stdout = """APP_DEBUG=true
+APP_NAME=myapp
+APP_PORT=8080"""
+env = {}
+
+[[test_cases]]
+stdin = """DB_HOST=localhost
+DB_PORT=5432"""
+expected_stdout = """DB_HOST=localhost
+DB_PORT=5432"""
+env = {}
+
+[[test_cases]]
+stdin = "SINGLE_VAR=hello"
+expected_stdout = "SINGLE_VAR=hello"
+env = {}