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/pipeline/csv_transform.toml

@@ -0,0 +1,29 @@
+name = "csv_transform"
+category = "pipeline"
+mode = "convert"
+description = """
+Read CSV data from stdin. The first line is a header.
+Each subsequent line has fields: name,age,city
+Print each record as "name is age years old and lives in city", one per line.
+Skip the header in the output.
+"""
+
+bash_source = """
+#!/bin/bash
+read -r header  # skip header
+while IFS=',' read -r name age city || [[ -n "$name" ]]; do
+    echo "$name is $age years old and lives in $city"
+done
+"""
+
+[[test_cases]]
+stdin = """name,age,city
+Alice,30,Paris
+Bob,25,London"""
+expected_stdout = """Alice is 30 years old and lives in Paris
+Bob is 25 years old and lives in London"""
+
+[[test_cases]]
+stdin = """name,age,city
+Charlie,40,Tokyo"""
+expected_stdout = "Charlie is 40 years old and lives in Tokyo"

tasks/pipeline/log_parser.toml

@@ -0,0 +1,34 @@
+name = "log_parser"
+category = "pipeline"
+mode = "convert"
+description = """
+Read log lines from stdin. Each line has the format: "LEVEL: message"
+where LEVEL is one of ERROR, WARN, INFO.
+Count occurrences of each level and print a summary sorted by level name.
+Format: "LEVEL: count"
+"""
+
+bash_source = """
+#!/bin/bash
+while IFS= read -r line || [[ -n "$line" ]]; do
+    echo "${line%%:*}"
+done | sort | uniq -c | while read -r count level; do
+    echo "$level: $count"
+done
+"""
+
+[[test_cases]]
+stdin = """ERROR: disk full
+INFO: started
+WARN: low memory
+ERROR: timeout
+INFO: completed"""
+expected_stdout = """ERROR: 2
+INFO: 2
+WARN: 1"""
+
+[[test_cases]]
+stdin = """INFO: boot
+INFO: ready
+INFO: shutdown"""
+expected_stdout = "INFO: 3"

tasks/pipeline/pipeline_transform.toml

@@ -0,0 +1,38 @@
+name = "pipeline_transform"
+category = "pipeline"
+mode = "solve"
+description = """
+Read lines from stdin. Build a pipeline that:
+1. Filters to only lines containing the word "error" (case-insensitive)
+2. Extracts the portion after the first colon (trimming leading whitespace)
+3. Sorts the results alphabetically
+4. Removes duplicate lines
+
+Print the final result to stdout, one line per line.
+"""
+
+[[test_cases]]
+stdin = """INFO: server started
+ERROR: disk full
+WARN: low memory
+error: connection refused
+ERROR: disk full
+INFO: request handled
+Error: timeout reached"""
+expected_stdout = """connection refused
+disk full
+timeout reached"""
+
+[[test_cases]]
+stdin = """ERROR: alpha
+ERROR: charlie
+ERROR: bravo
+ERROR: alpha"""
+expected_stdout = """alpha
+bravo
+charlie"""
+
+[[test_cases]]
+stdin = """INFO: all good
+WARN: nothing here"""
+expected_stdout = ""

tasks/pipeline/pipeline_word_freq.toml

@@ -0,0 +1,37 @@
+name = "pipeline_word_freq"
+category = "pipeline"
+mode = "convert"
+description = """
+Read text from stdin. Count the frequency of each word (case-insensitive, only alphabetic characters count as words).
+Print the top 5 most frequent words in descending order of frequency, in the format:
+"count word"
+If two words have the same count, sort them alphabetically.
+If there are fewer than 5 unique words, print all of them.
+"""
+
+bash_source = """
+#!/bin/bash
+tr '[:upper:]' '[:lower:]' | tr -cs '[:alpha:]' '\n' | grep -v '^$' | sort | uniq -c | sort -k1,1rn -k2,2 | head -5 | while read -r count word || [[ -n "$word" ]]; do
+    echo "$count $word"
+done
+"""
+
+[[test_cases]]
+stdin = """The quick brown fox jumps over the lazy dog.
+The dog barked at the fox. The fox ran away."""
+expected_stdout = """5 the
+3 fox
+2 dog
+1 at
+1 away"""
+
+[[test_cases]]
+stdin = "hello hello world"
+expected_stdout = """2 hello
+1 world"""
+
+[[test_cases]]
+stdin = "One one ONE two TWO two Three three three three"
+expected_stdout = """4 three
+3 one
+3 two"""